TWI653907B - A driver circuit for a light source, and a controller for luminance and color temperature - Google Patents

Abstract

The invention discloses a light source driving circuit and a brightness and color temperature controller. The light source driving circuit is configured to adjust the brightness and color temperature of the light source, and includes a power converter and a brightness and color temperature controller coupled to the power converter. The power converter is coupled between the power source and the light source, receives power from the power source, and provides the adjusted power to the light source. The brightness and color temperature controller receives a conduction detection signal indicative of an on state of the three-terminally controlled dimmer coupled between the power source and the power converter, and adjusts the brightness of the light source based on the conduction detection signal. The brightness and color temperature controller also receives a switch monitoring signal indicative of the operation of the on/off switch coupled to the three-terminal remote control dimmer, and adjusts the color temperature of the light source based on the switch monitoring signal.

Description

Light source drive circuit and brightness and color temperature controller

The invention relates to the field of light source control, in particular to a light source driving circuit and a brightness and color temperature controller.

In recent years, new light sources such as light-emitting diodes (LEDs) have made advances in materials and manufacturing. LEDs are characterized by high efficiency, long life and bright colors, and can be used in automobiles, computers, communications, military and daily necessities. For example, LED lights can replace traditional incandescent lamps as illumination sources.

The light source can be adjusted in different ways. For example, the power converter receives the AC voltage provided by the AC power source and generates a DC voltage to power the LED light source. The controller adjusts the output of the power converter according to a dimmer coupled between the alternating current power source and the power converter to adjust the brightness of the LED light source. The dimmer can be a three-terminal TRIAC dimmer or an on/off dimmer. However, this dimmer can only be used to adjust the brightness of the light source and not to adjust the color temperature of the light source.

The technical problem to be solved by the present invention is to provide a light source driving circuit and a brightness and color temperature controller, which can adjust the brightness and color temperature of the light source in a simple and convenient manner.

The present invention provides a light source driving circuit that adjusts the brightness and color temperature of a light source. The method includes: a power converter coupled between the power source and the light source, receiving power from the power source and providing the adjusted power to the light source; and a brightness and color temperature controller coupled to the power converter, the receiving indication coupled to the a conduction detection signal of a conduction state of the TRIAC dimmer between the power source and the power converter, and adjusting a brightness of the light source based on the conduction detection signal, wherein the brightness and color temperature controller further receives an indication coupled to the TRIAC The switch of the operation of the dimmer's ON/OFF switch monitors the signal and adjusts the color temperature of the source based on the switch monitor signal.

The present invention also provides a brightness and color temperature controller comprising: a signal generator for generating a monitoring signal proportional to an average current flowing through the light source; and a TRIAC monitor for receiving a TRIAC coupled between the power source and the power converter a conduction detection signal of the on state of the dimmer, and generating a reference signal indicating a target value of the average current flowing through the light source according to the conduction detection signal; a driver coupled to the signal generator and the TRIAC monitor, according to the Monitoring a signal and the reference signal to generate a drive signal to control the power converter to provide regulated power to the light source; and a color temperature control unit to receive switch monitoring indicating operation of an ON/OFF switch coupled to the TRIAC dimmer Signaling, and adjusting the color temperature of the light source based on the switch monitoring signal.

Compared with the prior art, the light source driving circuit and the brightness and color temperature controller of the present invention can simultaneously adjust the brightness and color temperature of the light source through operation of a power switch (for example, including an ON/OFF switch and a TRIAC dimmer). No need to use additional dedicated components, it is simple and convenient and saves costs.

100‧‧‧Light source drive circuit

101‧‧‧Power switch

102‧‧‧ON/OFF switch

104‧‧‧Dimmer

106‧‧‧Rectifier

108‧‧‧Power Converter

110‧‧‧Transformers

112‧‧‧Brightness and color temperature controller

120‧‧‧First LED chain

122‧‧‧First control switch

130‧‧‧Second LED chain

132‧‧‧Second control switch

202‧‧‧TRIAC components

204‧‧‧Variable resistor

206‧‧‧ Capacitance

208‧‧‧DIAC components

300‧‧‧Light source drive circuit

302‧‧‧ filter

305‧‧‧ primary winding

307‧‧‧secondary winding

309‧‧‧Auxiliary winding

311‧‧‧ magnetic core

402‧‧‧ Acquisition circuit

404‧‧‧State detector

406‧‧‧Switch control signal

408‧‧‧Multiple selector

410‧‧‧Signal Generator

412‧‧‧ square wave signal

414‧‧‧Operational Amplifier

416‧‧‧ Capacitance

418‧‧‧Operational Transducer

420‧‧‧Sawtooth generator

422‧‧‧ error signal

426‧‧‧ comparator

428‧‧‧buffer

430‧‧‧ drive

432‧‧‧TRIAC monitor

434‧‧‧Determining unit

436‧‧‧Inverter

438‧‧‧Starting and low voltage locking circuit

440‧‧‧Color temperature control unit

502‧‧ ‧ voltage divider

504‧‧‧Division signal

506‧‧‧ comparator

508‧‧‧ square wave signal

510‧‧‧ filter

602‧‧‧Timer

604‧‧‧First D flip-flop

606‧‧‧Second D forward and reverse

608‧‧‧First Gate

610‧‧‧Second Gate

Fig. 1A is a block diagram of a light source driving circuit according to an embodiment of the present invention.

Fig. 1B is a block diagram of a light source driving circuit according to an embodiment of the present invention.

Figure 1C is a waveform diagram of the signal generated or received by the TRIAC dimmer in Figure 1B.

Figure 2 is a schematic illustration of one embodiment of a power switch in Figures 1A and 1B.

Fig. 3 is a circuit diagram of a light source driving circuit according to an embodiment of the present invention.

Fig. 4 is a schematic view showing the structure of the brightness and color temperature controller in Fig. 3.

Figure 5 is a schematic view showing the structure of the TRIAC monitor in Figure 4.

Figure 6 is a schematic view showing the structure of the color temperature control module in Fig. 4.

Fig. 7 is a signal waveform diagram of a light source driving circuit including the color temperature control module shown in Fig. 6 according to an embodiment of the present invention.

Fig. 8 is a signal waveform diagram of a light source driving circuit including the color temperature control module shown in Fig. 6 according to another embodiment of the present invention.

Figure 9 is a flow chart of a method of controlling the brightness and color temperature of a light source in accordance with an embodiment of the present invention.

A detailed description of the embodiments of the present invention will be given below. Although the invention has been illustrated and described with respect to the embodiments, it should be noted that the invention is not limited to the embodiments. Rather, the invention is to cover all modifications, alternatives and equivalents of the scope of the invention as defined by the appended claims. The following detailed description of the invention In the following, a number of specific details are set forth in order to provide a complete understanding of the invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details. In other instances, well-known schemes, procedures, components, and circuits have not been described in detail in order to facilitate the invention.

1A is a block diagram of a light source driving circuit 100 in accordance with an embodiment of the present invention. In one embodiment, the light source includes a first illuminating element (eg, a first LED chain 120) and a second illuminating element (eg, a second LED chain 130). The second LED chain 130 can have a different color temperature value than the first LED chain 120, for example, the first LED chain 120 has a first color temperature value and the second LED chain 130 has a second color temperature value. The power switch 101 coupled between the power source VIN and the light source driving circuit 100 includes an ON/OFF switch 102 (for example, a rocker switch) and a TRIAC dimmer 104 to selectively couple the power source VIN to the light source driving circuit 100. It is worth noting that although the ON/OFF switch 102 is coupled before the TRIAC dimmer 104 in FIG. 1A, this is not limiting. For example, the ON/OFF switch 102 can be coupled after the TRIAC dimmer 104. In one embodiment, the power switch 101 can be a power switch placed on a wall. As shown in FIG. 2, the power switch 101 is divided into an upper half TRIAC dimmer 104 and a lower half ON/OFF switch 102. In operation, by switching the ON/OFF switch 102 to the ON or OFF terminal, the conductive state of the power switch 101 can be controlled to be closed or opened by the user and transmitted through the operation of the ON/OFF switch 102 (eg, disconnected) Operation) to adjust the color temperature of the light source. At the same time, the user can also adjust the brightness of the light source by operating the TRIAC dimmer 104 (eg, knob operation).

The AC input voltage VIN from the power source is converted to an AC voltage VTRIAC via the ON/OFF switch 102 and the TRIAC dimmer 104. The light source driving circuit 100 includes a rectifier 106 for converting an alternating voltage VTRIAC into a rectified voltage VREC, coupled to the rectifier 106 and the light. A power converter 108 between the source (eg, the first LED chain 120 and the second LED chain 130), a brightness and color temperature controller 112, a first control switch 122, and a second control switch 132. Power converter 108 is operative to receive rectified voltage VREC from rectifier 106 and provide regulated output current IOUT to a source (eg, first LED chain 120 and second LED chain 130). Power converter 108 includes a transformer 110 having a primary winding and a secondary winding.

The brightness and color temperature controller 112 is coupled between the primary winding of the transformer 110 and the light source (eg, the first LED chain 120 and the second LED chain 130) for receiving an operation indicative of the ON/OFF switch 102 (eg, off) The switch of the open operation monitors the signal TS and adjusts the color temperature of the light source (eg, the first LED chain 120 and the second LED chain 130) based on the switch monitor signal TS. As shown in FIG. 1A, the luminance and color temperature controller 112 generates a first control signal CTR1 and a second control signal CTR2 according to the switch monitoring signal TS to control the first LED chain 120 and the second LED chain 130, respectively.

The first control signal CTR1 selectively turns on the first control switch 122 coupled between the brightness and color temperature controller 112 and the first LED chain 120 such that the color temperature of the light source is adjusted to a first color temperature value. The second control signal CTR2 selectively turns on the second control switch 132 coupled between the brightness and color temperature controller 112 and the second LED chain 130 such that the color temperature of the light source is adjusted to a second color temperature value. More specifically, if the first control signal CTR1 turns on the first control switch 122 coupled between the brightness and color temperature controller 112 and the first LED chain 120, the current ILED1 flows through the first LED chain 120 and the light source The color temperature is adjusted to a first color temperature value; if the second control signal CTR2 turns on the second control switch 132 coupled between the brightness and color temperature controller 112 and the second LED chain 130, the current ILED2 flows through the second LED chain 130 and the color temperature of the light source is adjusted to a second color temperature value.

In addition, the brightness and color temperature controller 112 is further configured to receive an indicator TRIAC dimmer The conduction detection signal TD of the conduction state of 104 (for example, the conduction angle between 0-180 degrees) is adjusted based on the conduction detection signal TD (for example, the value of the current ILED1 or the current ILED2). Specifically, the operation of adjusting the brightness can be understood in conjunction with FIGS. 1B and 1C, which is a block diagram of a light source driving circuit 100 including an ON/OFF switch 102 and a TRIAC dimmer 104 in accordance with an embodiment of the present invention. As shown in FIG. 1B, the TRIAC dimmer 104 includes a TRIAC element 202 coupled between the ON/OFF switch 102 and the rectifier 106. The TRIAC element 202 has 埠A1, 埠A2, and a gate G. The TRIAC dimmer 104 also includes a variable resistor 204 and a capacitor 206 coupled in series, and a Diode for Alternating Current (DIAC) component 208. One end of the DIAC component 208 is coupled to the capacitor 206 and the other end is coupled to the gate G of the TRIAC component 202. The TRIAC component 202 is a bidirectional switch that, when triggered, conducts current in either direction. The TRIAC element 202 can be triggered by a positive or negative current applied to the gate G. Once triggered, the TRIAC element 202 will remain conductive until the current flowing through 埠A1 and 埠A2 drops to a threshold (eg, hold current IH).

1C is a diagram showing signal waveforms generated or received by the TRIAC dimmer 104 of FIG. 1B, in accordance with one embodiment of the present invention. FIG. 1C will be described in conjunction with FIG. 1B. 1C shows the waveform of the AC input voltage VIN, the voltage VA2-A1 between 埠A1 and 埠A2 of the TRIAC element 202, the current IDIAC flowing through the DIAC element 208, the AC voltage VTRIAC, and the rectified voltage VREC.

In the example of Figure 1C, the AC input voltage VIN has a sinusoidal waveform. Between time T0 and time T1, the TRIAC element 202 is turned off, and the voltage VA2-A1 between 埠A1 and 埠A2 increases as the AC input voltage VIN increases. TRIAC element 202 remains conductive between time T1 and time T2. Therefore, between time T1 and time T2, the waveform of the alternating voltage VTRIAC coincides with the waveform of the alternating current input voltage VIN.

At time T2 near the end of the first half cycle of the AC input voltage VIN, The current flowing through the TRIAC element 202 drops below the holding current of the TRIAC element 202, and the TRIAC element 202 is turned off. During the second half of the AC input voltage VIN, when the voltage on capacitor 206 turns on the DIAC component 208 at time T3, the TRIAC component 202 is again turned on. Similarly, between time T3 and time T4, the waveform of the alternating voltage VTRIAC coincides with the waveform of the alternating current input voltage VIN.

In one embodiment, the user can adjust the resistance of the variable resistor 204 (R204), for example, by rotating the knob of the TRIAC dimmer 104 to adjust the resistance of the variable resistor 204. The resistance of the variable resistor 204 determines the turn-on timing of the TRIAC component 202 during each half cycle of the AC input voltage VIN. More specifically, in one embodiment, if the resistance of the variable resistor is increased, the average value of the charging current for charging the capacitor 206 after time T0 is decreased. Therefore, the voltage on capacitor 206 requires more time to reach the voltage threshold associated with DIAC component 208. Therefore, the turn-on timing of the TRIAC element 202 is delayed, for example, later than the time T1. Similarly, if the resistance of the variable resistor is reduced, the turn-on timing of the TRIAC element 202 is advanced, for example, earlier than the time T1. Therefore, by adjusting the resistance of the variable resistor 204, the turn-on timing of the TRIAC element 202 in each half cycle is adjusted accordingly, for example, the turn-on time is delayed or advanced. The TRIAC dimmer 104 can have other configurations and is not limited to the embodiment of Figures IB and 1C. In another embodiment, if the resistance of the variable resistor 204 changes, for example, the resistance is adjusted by the user, the turn-off instant of the TRIAC component 202 is adjusted during each half cycle. By way of example, in the following description, the TRIAC dimmer 104 adjusts the turn-on timing of the TRIAC element 202. However, the present invention is not limited thereto, and the TRIAC dimmer 104 of the present invention is also suitable for adjusting the turn-off timing of the TRIAC element 202.

Returning to FIGS. 1A and 1B, the luminance and color temperature controller 112 receives a turn-on detection signal indicative of the conductive state of the TRIAC element 202 (eg, a conduction angle between 0-180 degrees). TD, and adjusts the brightness of the light source (for example, the value of current ILED1 or current ILED2) based on the conduction detection signal TD. The luminance and color temperature controller 112 generates a drive signal DRV based on the turn-on detection signal TD. The drive signal DRV controls a control switch (eg, control switch Q3 in FIG. 3) in the power converter 108 to alternately operate in a first state (eg, an on state) and a second state (eg, an off state), thereby adjusting the flow The average current through the LED source (eg, current ILED1 or current ILED2). More specifically, in one embodiment, the luminance and color temperature controller 112 detects the turn-on instant of the TRIAC component 202 in each cycle based on the turn-on detection signal TD. If the resistance of the variable resistor 204 is increased (e.g., by rotating the knob of the TRIAC dimmer 104), the turn-on timing of the TRIAC element 202 is delayed in each cycle. Thus, the brightness and color temperature controller 112 controls the switch Q3 to reduce the average current flowing through the LED source (eg, the first LED chain 120 or the second LED chain 130). Similarly, if the resistance of the variable resistor 204 is reduced, the brightness and color temperature controller 112 controls the switch Q3 to increase the average current flowing through the LED source (eg, the first LED chain 120 or the second LED chain 130). As described above, for example, if the brightness and color temperature controller 112 generates the first control signal CTR1 according to the switch monitoring signal TS to turn on the first control switch 122 and adjust the color temperature of the light source to the first color temperature value, the brightness and color temperature controller The average current ILED1 flowing through the first LED light source 120 is adjusted according to the operation of the TRIAC dimmer 104. If the brightness and color temperature controller 112 generates the second control signal CTR2 according to the switch monitoring signal TS to turn on the second control switch 132 and adjust the color temperature of the light source to the second color temperature value, the brightness and color temperature controller 112 is based on the TRIAC dimmer The operation of 104 adjusts the average current ILED2 flowing through the second LED light source 130.

Advantageously, the brightness and color temperature controller 112 can not only adjust the color temperature of the light source (eg, the first LED chain 120 and the second LED chain 130) according to the operation of the ON/OFF switch 102, but can also be simultaneously based on the TRIAC dimmer 104. Operation to adjust the LED light source (eg, the first LED The brightness of the chain 120 and the second LED chain 130), without the need for additional dedicated components, is simple and convenient and saves cost. The operation of brightness and color temperature controller 112 will be further described in conjunction with FIG.

FIG. 3 is a circuit diagram of a light source driving circuit 300 according to an embodiment of the present invention. In Figure 3, the power supply VIN and TRIAC dimmer 104 are not shown for the sake of brevity. The light source driving circuit 300 is powered by the power source VIN (for example, 110/120 V ac, 60 Hz) via the ON/OFF switch 102 and the TRIAC dimmer 104. The AC voltage VTRIAC is converted to a rectified voltage VREC via a filter 302 and a rectifier 106 (eg, a bridge rectifier composed of diodes D1-D4). Power converter 108 receives rectified voltage VREC from rectifier 106 and provides regulated output current IOUT to a source (eg, first LED chain 120 and second LED chain 130).

In the example of FIG. 3, power converter 108 includes transformer 110, control switch Q3, diode D5, and capacitor C8. The transformer 110 includes a primary winding 305 for receiving a rectified voltage VREC from the rectifier 106, a secondary winding 307 for supplying an output current IOUT to the first LED chain 120 and the second LED chain 130, a magnetic core 311, and for luminance The color temperature controller 112 provides an auxiliary winding 309 of voltage. The transformer 110 shown in FIG. 3 includes three windings by way of example and not limitation. In other embodiments, the transformer 110 can include other different numbers of windings. In the embodiment shown in FIG. 3, control switch Q3 coupled to primary winding 305 is external to luminance and color temperature controller 112. In other embodiments, control switch Q3 can also be integrated into the interior of brightness and color temperature controller 112.

The brightness and color temperature controller 112 is coupled to the primary winding 305 and the auxiliary winding 309 of the transformer 110. The brightness and color temperature controller 112 can be a flyback pulse width modulation (PWM) controller for generating a PWM signal to selectively turn on the control switch Q3 in series with the primary winding 305 and to adjust the duty cycle of the PWM signal. The output current IOUT of the transformer 110 is adjusted. By way of example and not limitation, the luminance and color temperature controller 112 includes 埠HV, CLK, PWM, VDD, GND, COMP, CS, FB, SW1, and SW2.

The luminance and color temperature controller 112 receives the conduction detection signal TD of the rectified voltage VIN at 埠HV and adjusts the average current (eg, current ILED1 or current ILED2) flowing through the LED light source according to the conduction detection signal TD. In particular, the turn-on detection signal TD may indicate the on state of the TRIAC element 202 in the TRIAC dimmer 104 (eg, a conduction angle between 0-180 degrees). The luminance and color temperature controller 112 may provide a reference signal REF corresponding to the conduction angle of the TRIAC dimmer 104 based on the conduction detection signal TD (as detailed in FIGS. 4 and 5 below), and generate at the 埠PWM according to the reference signal REF. The signal DRV is driven to adjust the average current flowing through the LED source (eg, current ILED1 or current ILED2).

Advantageously, in response to the rotational operation of the TRIAC dimmer 104 in the primary circuit, the brightness of the light sources (eg, the first LED chain 120 and the second LED chain 130) in the secondary circuit is adjusted by the luminance and color temperature controller 112. The target brightness value (eg, 25%, 50%, 75%, 90%, 100%, etc.) corresponding to the conduction angle of the TRIAC dimmer 104.

The brightness and color temperature controller 112 receives a switch monitoring signal TS indicating a conduction state (eg, an on or off state) of the ON/OFF switch 102 at 埠CLK, and generates a first control signal CTR1 according to the switch monitoring signal TS (at埠SW1) and a second control signal CTR2 (at 埠SW2) to control the first LED chain 120 and the second LED chain 130, respectively. More specifically, in one embodiment, if the switch monitor signal TS indicates that the ON/OFF switch 102 is turned "on" for the first time, the luminance and color temperature controller 112 generates a first control signal CTR1 to turn on the first control switch 122 and A second control signal CTR2 is generated to turn off the second control switch 132, so that the current ILED1 flows through the first LED chain 120 without current flowing through the second LED chain 130; if the switch monitoring signal TS indicates The ON/OFF switch 102 is turned off and turned "on" again for a predetermined period of time, and the luminance and color temperature controller 112 generates a first control signal CTR1 to turn off the first control switch 122 and generate a second control signal CTR2 to turn on the second Switch 132 is controlled such that no current flows through first LED chain 120 and current ILED2 flows through second LED chain 130. Because the second LED chain 130 can have a different color temperature than the first LED chain 120, the brightness and color temperature controller 112 can adjust the color temperature of the light source based on the switch monitoring signal TS.

The 埠FB receives a current monitoring signal SEN indicating a current IS flowing through the secondary winding 307 from a voltage dividing circuit (not shown) coupled to the auxiliary winding 309 of the transformer 110 (eg, the current monitoring signal SEN may indicate flow through the secondary side) When the current IS of the winding 307 drops to 0). The 埠CS receives a monitor signal LPSEN indicating the current IP flowing through the primary winding 305. The brightness and color temperature controller 112 receives the current monitor signal SEN and the monitor signal LPSEN and generates a drive signal DRV at the 埠PWM to control the control switch Q3 to regulate the output current IOUT of the power converter 108. The brightness and color temperature controller 112 controls the conduction state (eg, the on or off state) of the control switch Q3 based on the current monitoring signal SEN and the monitor signal LPSEN generating the drive signal DRV at the 埠PWM. For example, when the current monitoring signal SEN indicates that the current IS flowing through the secondary winding 307 falls to zero, the drive signal DRV can switch the control switch Q3 from the off state to the on state. More specifically, the voltage of the current monitoring signal SEN can be compared with the voltage of the reference signal indicating the target current value ITARGET flowing through the light source; the voltage of the monitoring signal LPSEN can be made with the voltage of another reference signal indicating the target current value ITARGET Comparison. If any of the comparison results indicate that the transient current value flowing through the light source is greater than the target current value ITARGET, the luminance and color temperature controller 112 reduces the duty cycle of the drive signal DRV and vice versa. In one embodiment, if the drive signal DRV is in a first state (eg, a logic high), the control switch Q3 is turned on, current flows through the primary winding 305, and the core 311 for energy storage. If the drive signal DRV is in the second state (eg, logic low), the control switch Q3 is turned off, and the diode D5 coupled to the secondary winding 307 is forward biased to transmit the energy stored in the magnetic core 311. The secondary winding 307 is released to the capacitor C8 and the light source. Therefore, the power of the light sources (eg, the first LED chain 120 and the second LED chain 130) can be adjusted according to the drive signal DRV.

埠 VDD is coupled to the auxiliary winding 309. In one embodiment, an energy storage unit (eg, capacitor C5) coupled between 埠VDD and ground supplies power to the luminance and color temperature controller 112 when the ON/OFF switch 102 is turned off.埠COMP is coupled to ground (埠GND) through a capacitor to provide an error signal.

Advantageously, in response to the opening operation of the ON/OFF switch 102 in the primary circuit, after the ON/OFF switch 102 is turned on again within a predetermined period of time after the OFF operation of the ON/OFF switch 102, the secondary circuit is The color temperature of the light source (eg, first LED chain 120 and second LED chain 130) is adjusted by brightness and color temperature controller 112 to a target color temperature value (eg, a first color temperature value or a second color temperature value).

4 is a block diagram showing the structure of the brightness and color temperature controller 112 of FIG. Figure 4 will be described in conjunction with Figure 3. In the example of FIG. 4, the brightness and color temperature controller 112 is divided into a brightness control module of the upper half and a color temperature control module of the lower half.

The brightness control module works as follows:

The brightness control module includes a signal generator 410, a TRIAC monitor 432, and a driver 430. Signal generator 410 generates a monitoring signal (e.g., square wave signal 412). The average voltage of the monitoring signal is proportional to the average current IOUT (eg, current ILED1 or ILED2) flowing through the LED source (eg, first LED chain 120 or second LED chain 130). The TRIAC monitor 432 generates the reference signal REF based on the conduction detection signal TD. The reference signal REF indicates the flow through the LED light source (example) For example, the target current value of the average current of the first LED chain 120 or the second LED chain 130) (eg, the target current value ITARGET). Accordingly, the driver 430 generates the drive signal DRV based on the square wave signal 412 and the reference signal REF. Signal generator 410, driver 430 and transformer 110 form a negative feedback loop. The negative feedback loop maintains the average voltage of the square wave signal 412 equal to the reference signal REF, thereby maintaining the average current IOUT flowing through the LED source (eg, the first LED chain 120 or the second LED chain 130) equal to the target current value ITARGET. Please note that the conduction angle of the TRIAC dimmer 104 can be changed as the user rotates, so the reference signal REF also changes accordingly. In this way, the adjustment of the brightness of the LED light source is achieved.

Signal generator 410 includes acquisition circuitry 402, state detector 404, and multiplexer 408. The acquisition circuit 402 is coupled to the 埠CS to receive a monitor signal LPSEN indicative of the current flowing through the primary winding 305. The acquisition circuit 402 samples and holds according to the monitor signal LPSEN and generates a peak signal VPK that is proportional to the peak value of the current flowing through the primary winding 305. In one embodiment, multiplexer 408 includes a switch having a first turn, a second turn, and a third turn. The first port of the multiplexer 408 is coupled to the output of the acquisition circuit 402 for receiving the peak signal VPK. The second port of the multiplexer 408 is coupled to the reference ground GND for receiving a preset voltage signal VPRE (eg, VPRE is zero volts). A third port of multiplexer 408 is coupled to the input of driver 430 for providing a square wave signal 412. In another embodiment, the second turn of the multiplexer 408 can also be coupled to other signal generators to receive a predetermined constant reference voltage.

State detector 404 is coupled to 埠FB to receive current monitoring signal SEN. The state detector 404 determines whether the transformer 110 is operating in a preset state based on the current monitoring signal SEN and generates a switch control signal 406 to control the multiplexer 408. More specifically, in one embodiment, when the current monitoring signal SEN has a first voltage value indicating that the transformer 110 is operating in a preset state The switch control signal 406 has a first state (eg, a high potential). At this time, the first and third turns of the multiplexer 408 are turned on. Thus, the square wave signal 412 is equal to the peak signal VPK. When the current monitoring signal SEN has a second voltage value indicating that the transformer 110 is not operating in a preset state, the switch control signal 406 has a second state (eg, a low potential). At this time, the second and third turns of the multiplexer 408 are turned on. Thus, the square wave signal 412 is equal to the preset voltage signal VPRE.

Advantageously, the TRIAC monitor 432 is capable of adjusting the reference signal REF in accordance with the TRIAC dimmer 104. More specifically, in one embodiment, if the turn-on detection signal TD indicates that the turn-on instant of the TRIAC element 202 in each cycle is advanced (ie, the turn-on angle is increased), the TRIAC monitor 432 increases the reference signal REF. Thereby, the average current flowing through the LED light source (eg, the first LED chain 120 or the second LED chain 130) increases. Similarly, if the conduction detection signal TD indicates that the conduction time of the TRIAC element 202 in each cycle is delayed (ie, the conduction angle is decreased), the TRIAC monitor 432 reduces the reference signal REF. Thus, the average current flowing through the LED light source (eg, the first LED chain 120 or the second LED chain 130) is reduced. The brightness control module can have other configurations and is not limited to the embodiment of FIG.

FIG. 5 is a block diagram showing the structure of the TRIAC monitor 432 of FIG. 4 in accordance with one embodiment of the present invention. Figure 5 will be described in conjunction with Figure 4. In the example of FIG. 5, the TRIAC monitor 432 includes a voltage divider 502, a comparator 506, and a filter 510. In one embodiment, voltage divider 502 includes a resistor R7 and a resistor R8 coupled in series. The voltage divider 502 receives the turn-on detection signal TD and provides a divided voltage signal 504 indicative of the rectified voltage VIN. The comparator 506 compares the divided voltage signal 504 with the threshold voltage VTH and generates a square wave signal 508 based on the comparison result. Filter 510 filters square wave signal 508 to produce reference signal REF.

More specifically, in one embodiment, conduction at time T1 to time T2 Within time TTRI_ON, the divided voltage signal 504 is greater than the threshold voltage VTH (eg, zero volts) and the square wave signal 508 is switched to a high potential. In the off time TTRI_OFF from time T2 to time T3, the divided voltage signal 504 is smaller than the threshold voltage VTH, and the square wave signal 508 is switched to the low potential. When the conduction time of the TRIAC element 202 changes, the average voltage of the square wave signal 508 changes accordingly. Filter 510 filters square wave signal 508 to provide a reference signal REF that is proportional to the average voltage of square wave signal 508. Therefore, the average current through the LED light source (eg, the first LED chain 120 or the second LED chain 130) is tunably rectified by adjusting the reference signal REF, thereby implementing the LED light source according to the TRIAC dimmer 104 (eg, the first LED) Dimming control of chain 120 or second LED chain 130). The TRIAC monitor 432 can have other configurations and is not limited to the embodiment of FIG.

The driver 430 includes an operational amplifier 414, a sawtooth generator 420, a comparator 426, and a buffer 428. In one embodiment, operational amplifier 414 includes an Operational Transconductance Amplifier (OTA) 418 and a capacitor 416. The forward input of the operational transconductance amplifier 418 receives the square wave signal 412 and the inverting input receives the reference signal REF. Wherein, the reference signal REF represents the target current value ITARGET of the output current ILED1 or ILED2. The operational transconductance amplifier 418 generates a current I418 at the output based on the difference between the square wave signal 412 and the reference signal REF to charge or discharge the capacitor 416, thereby generating an error signal 422. Since capacitor 416 filters the ripple on error signal 422, error signal 422 is determined by the difference between the average voltage of square wave signal 412 (VSQ_AVG) and reference signal REF. In another embodiment, capacitor 416 is coupled to operational transduction amplifier 418 via a sigma of the controller outside of luminance and color temperature controller 112.

The sawtooth generator 420 generates a sawtooth wave signal SAW. Comparator 426 compares error signal 422 and sawtooth signal SAW and produces a comparison signal. Buffer 428 receives the comparison signal, And generating a drive signal DRV (eg, a pulse width modulated signal). In the embodiment of FIG. 4, if the average voltage of the square wave signal 412 increases, the error signal 422 increases, and the sawtooth signal SAW requires more time to increase to the error signal 422. Thereby, the duty cycle of the drive signal DRV is reduced, thereby reducing the average current of the output current ILED1 or ILED2 until the average voltage of the square wave signal 412 is reduced to the reference signal REF. Similarly, if the average voltage of the square wave signal 412 decreases, the duty cycle of the drive signal DRV increases, thereby increasing the average current of the output current ILED1 or ILED2 until the average voltage of the square wave signal 412 increases to the reference signal REF. In this way, the average current of the output current ILED1 or ILED2 can be adjusted to be equal to the target current value ITARGET, ie to achieve brightness control of the light source (eg, the first LED chain 120 and the second LED chain 130).

In addition, the color temperature control module works as follows:

FIG. 6 is a schematic structural view of the color temperature control module of FIG. 4. 4 and 6, the color temperature control module includes a determination unit 434, an inverter 436, a start and low voltage lock (UVL) circuit 438, and a color temperature control unit 440.

A startup and low voltage lock (UVL) circuit 438 is coupled to 埠VDD for selectively activating one or more components within the brightness and color temperature controller 112 based on different electrical conditions.

In one embodiment, if the voltage on 埠 VDD is higher than the first predetermined voltage, the startup and low voltage lockout circuit 438 will activate all of the components in the luminance and color temperature controller 112. When the ON/OFF switch 102 is turned off, if the voltage on 埠 VDD is lower than the second predetermined voltage, the startup and low voltage lockout circuit 438 will turn off some of the components of the luminance and color temperature controller 112 to conserve power. If the voltage on 埠 VDD is lower than the third predetermined voltage, the startup and low voltage lockout circuit 438 will turn off all components. In one embodiment, the first preset voltage is higher than the second preset voltage, and the second pre- Set the voltage higher than the third preset voltage.

The determining unit 434 detects the power state of the brightness and color temperature controller 112, and generates a first determination signal VDD_L and a second determination signal VDD_H based on the power state of the brightness and color temperature controller 112. The luminance and color temperature controller 112 adjusts the color temperature of the light source based on the first determination signal VDD_L, the second determination signal VDD_H, and the switch monitoring signal TS. For example, if the voltage at the 埠VDD of the luminance and color temperature controller 112 is less than the reset threshold voltage (eg, 4V), the first decision signal VDD_L has a first state (eg, a logic high); if the luminance and color temperature controller The voltage at 埠VDD of 112 is greater than the reset threshold voltage (eg, 4V), then the first decision signal VDD_L has a second state (eg, a logic low); if the voltage at the 埠VDD of the luminance and color temperature controller 112 is less than When the threshold voltage is enabled (eg, 10V), the second decision signal VDD_H has a first state (eg, a logic low); if the voltage at the 埠VDD of the luminance and color temperature controller 112 is greater than the enable threshold voltage (eg, 10V) Then, the second determination signal VDD_H has a second state (for example, a logic high potential).

The color temperature control unit 440 is configured to generate the first control signal CTR1 and the second control signal CTR2 according to the switch monitoring signal TS, the first determination signal VDD_L, and the second determination signal VDD_H to control the first LED chain 120 and the second LED chain 130, respectively. In one embodiment, color temperature control unit 440 includes a timer 602, a first D flip-flop 604, a second D flip-flop 606, a first AND gate 608, and a second AND gate 610. The timer 602 receives the switch monitor signal TS and starts timing when the switch monitor signal TS has a falling edge. The timer 602 also generates a pulse signal TS_DE after a predefined time interval Δt of each falling edge of the switch monitoring signal TS. The pulse signal TS_DE is coupled to the input 埠CLK of the first D flip-flop 604, and the switch monitoring signal TS is coupled to the input 埠CLK of the second D flip-flop 606. The input 埠D1 of the first D flip-flop 604 is coupled to its output埠 And the output 埠Q1 of the first D flip-flop 604 is coupled to the input 埠D2 of the second D flip-flop 606.

The input 埠R of the first D flip-flop 604 and the second D flip-flop 606 are both coupled to the output 埠 of the inverter 436, and the input 埠 of the inverter 436 is coupled to the determining unit 434. If the voltage at the 埠VDD of the luminance and color temperature controller 112 is less than the reset threshold voltage (eg, 4V), the first decision signal VDD_L is logic high, then the first D flip-flop 604 and the second D flip-flop 606 Both are reset by the inverter 436. Therefore, both the output 埠Q1 of the first D flip-flop 604 and the output 埠Q2 of the second D flip-flop 606 are reset to a logic low level, and the output of the first D flip-flop 604 埠 And the output of the second D flip-flop 606 Both are reset to logic high.

The second determination signal VDD_H and the output 埠Q2 of the second D flip-flop 606 are both coupled to the first AND gate 608, and the first AND gate 608 generates a first control signal CTR1 to control the first control switch 122 and flow through the first Current ILED1 of LED chain 120. The second determination signal VDD_H and the output 埠Q2 of the second D flip-flop 606 are both coupled to the second AND gate 610, and the second AND gate 610 generates a second control signal CTR2 to control the second control switch 132 and flow through the second Current ILED2 of LED chain 130. In this manner, the brightness and color temperature controller 112 can adjust the color temperature of the light source in response to the opening operation of the ON/OFF switch 102.

Fig. 7 is a signal waveform diagram of a light source driving circuit including the color temperature control module shown in Fig. 6. 7 shows the switch monitor signal TS, the pulse signal TS_DE, the first decision signal VDD_L, the second decision signal VDD_H, the voltage at the input 埠D1, the voltage at the output 埠Q1, the voltage at the output 埠Q2, the first control Signal waveforms of the signal CTR1 and the second control signal CTR2. Figure 7 will be described in conjunction with Figures 3 and 6.

At time t0, the ON/OFF switch 102 is turned on. At time t1, the switch monitor signal TS changes from a first state (eg, a logic low potential) to a second state (eg, a logic high potential), The voltage at VDD increases to a reset threshold voltage (eg, 4V) and the first decision signal VDD_L changes from a first state (eg, a logic high) to a second state (eg, a logic low). At time t2, the voltage at VDD increases to an enable threshold voltage (eg, 10V) and the second decision signal VDD_H changes from a first state (eg, a logic low) to a second state (eg, a logic high) . The output 埠Q1 of the first D flip-flop 604 and the output 埠Q2 of the second D flip-flop 606 are both logic low during the time interval from time t0 to time t2. Since the second determination signal VDD_H received by the first AND gate 608 and the second AND gate 610 is logic low, the first control signal CTR1 and the second control signal CTR2 are also logic low. After the time t2, since the second determination signal VDD_H changes to a logic high level, the first control signal CTR1 also changes to a logic high level. Thus, the first control switch 122 is turned "on" and the current ILED1 begins to flow through the first LED chain 120. At time t3, the ON/OFF switch 102 is turned off, and the voltage at the 埠VDD of the luminance and color temperature controller 112 begins to drop. As described above, once the switching monitor signal TS has a falling edge, the pulse signal TS_DE can be generated after the predefined time interval Δt. At time t4, in response to the rising edge of the pulse signal TS_DE, the input 埠D1 of the first D flip-flop 604 changes from a logic high level to a logic low level, and the output 埠Q1 of the first D flip-flop 604 is logic low. The potential changes to a logic high. At time t5, the voltage at 埠VDD is lowered to an enable threshold voltage (eg, 10V), and the second decision signal VDD_H is changed from the second state (eg, logic high) to the first state (eg, logic low) . Therefore, since the second determination signal VDD_H received by the first AND gate 608 and the second AND gate 610 is logic low, the first control signal CTR1 and the second control signal CTR2 are also logic low.

At time t6, a rising edge of the switch monitor signal TS indicates that the ON/OFF switch 102 is turned "on" again. The time interval from time t3 to time t6 is less than a predetermined (prescribed) time interval (eg, t6-t3 < 3 seconds) to maintain the voltage at 埠 VDD above a reset threshold voltage (eg, 4V) and the first decision signal VDD_L remains at a logic low. In response to the rising edge of the switch monitor signal TS, the output 埠Q2 of the second D flip-flop 606 changes from a logic low to a logic high, and its output埠 Change from logic high to logic low. Similar to the time interval from time t1 to time t2, the time interval from time t6 to time t7, the first control signal CTR1 and the second control signal CTR2 are both logic low. After time t7, the voltage at 埠VDD increases above the enable threshold voltage, the second decision signal VDD_H changes to a logic high level, and the second control signal CTR2 also changes to a logic high level, and the second control switch 132 is turned on. And the current ILED2 begins to flow through the second LED chain 130. Then, the ON/OFF switch 102 is turned off again, and at time t8, the voltage at VDD is lowered to an enable threshold voltage (for example, 10 V). The signal waveform in the time interval from time t8 to time t10 is similar to the signal waveform in the time interval from time t0 to time t5. At time t9, the first control switch 122 is turned "on" and the current ILED1 begins to flow through the first LED chain 120.

Therefore, the brightness and color temperature controller 112 alternately turns on the first control switch 122 and the second control switch 132 in response to the OFF operation of the ON/OFF switch 102. Since the second LED chain 130 can have a different color temperature than the first LED chain 120, the brightness and color temperature controller 112 can adjust the color temperature of the light source in response to the opening operation of the ON/OFF switch 102.

FIG. 8 is a signal waveform diagram of a light source driving circuit including the color temperature control module shown in FIG. 6 according to another embodiment of the present invention. 8 shows the switch monitor signal TS, the pulse signal TS_DE, the first decision signal VDD_L, the second decision signal VDD_H, the voltage at the input 埠D1, the voltage at the output 埠Q1, the voltage at the output 埠Q2, the first control Signal waveforms of the signal CTR1 and the second control signal CTR2. FIG. 8 will be described in conjunction with FIGS. 3, 6, and 7.

The waveform in the time interval from the time t0 to the time t6' is similar to the waveform in the time interval from the time t0 to the time t6 in Fig. 7. At time t7', the ON/OFF switch 102 is turned on again. The time interval from the time t3 to the time t7' is greater than the predetermined time interval (e.g., t7'-t3 > 3 seconds). Therefore, at time t6', the voltage at 埠VDD is lowered to the reset threshold voltage (for example, 4V), and the first decision signal VDD_L is changed from the logic low level to the logic high level, and both the output 埠Q1 and the output 埠Q2 are emphasized. Set to logic low. Since the second determination signal VDD_H received by the first AND gate 608 and the second AND gate 610 is logic low, the first control signal CTR1 and the second control signal CTR2 are also logic low.

At time t8', the switch monitor signal TS changes from a first state (eg, a logic low) to a second state (eg, a logic high), and the voltage at VDD increases to a reset threshold voltage (eg, 4V) And the first determination signal VDD_L is changed from the first state (for example, a logic high potential) to the second state (for example, a logic low potential). At time t9', the voltage at VDD increases to an enable threshold voltage (eg, 10V), and the second decision signal VDD_H changes from a first state (eg, a logic low) to a second state (eg, a logic high) Potential). The signal waveform in the time interval from the time t7' to the time t9' is similar to the signal waveform in the time interval from the time t0 to the time t2. After the time t9', the voltage at 埠VDD increases above the enable threshold voltage, the second decision signal VDD_H changes to a logic high level, and the first control signal CTR1 also changes to a logic high level. Then, the first control switch 122 is turned on and the current ILED1 begins to flow through the first LED chain 120.

As shown in FIG. 7, if the switch monitoring signal TS indicates that the time interval between the OFF operation of the ON/OFF switch 102 and the next ON operation is less than a predetermined time interval (for example, 3 seconds), the brightness and color temperature controller 112 The light source is responded to the next turn-on operation of the ON/OFF switch 102 (example) For example, the color temperature of the first LED chain 120 and the second LED chain 130) is changed from the first color temperature value to the second color temperature value. More specifically, in the example of FIG. 7, during the first time interval (eg, the time interval from time t2 to time t5), the first control signal CTR1 is at a logic high level, and the first LED chain 120 is turned on. The second LED chain 130 is turned off to adjust the color temperature of the light source to a first color temperature value; during a second time interval different from the first time interval (eg, a time interval from time t7 to time t8), second The control signal CTR2 is at a logic high level, the first LED chain 120 is turned off, and the second LED chain 130 is turned on so that the color temperature of the light source is adjusted to the second color temperature value. Accordingly, the brightness and color temperature controller 112 changes the color temperature of the light source from the color temperature of the first LED chain 120 to the color temperature of the second LED chain 130 by alternately turning on the first control switch 122 and the second control switch 132. However, as shown in FIG. 8, if the switch monitor signal TS indicates that the time interval between the OFF operation of the ON/OFF switch 102 and the next ON operation is greater than a predetermined time interval (for example, 3 seconds), the brightness and color temperature control are performed. The timer 112 resets the color temperature of the light source to a preset color temperature value in response to the next ON operation of the ON/OFF switch 102. In the example of FIG. 8, the preset color temperature value may be a color temperature value of the first LED chain 120, for example, a color temperature value set by the factory; the preset color temperature value is not limited to the color temperature value shown in the example of FIG.

9 is a flow chart 900 of a method of controlling brightness and color temperature of a light source in accordance with an embodiment of the present invention. Figure 9 will be described in conjunction with Figures 1A-8. The specific steps covered in Figure 9 are merely examples, i.e., the present invention is applicable to steps that perform various other steps or that improve the steps expressed in Figure 9.

In step 902, a drive circuit (eg, light source drive circuit 100 or 300) receives electrical energy from a power source and is directed by a power converter (eg, power converter 108) to a light source (eg, first LED chain 120 and second LED chain 130) Provides regulated power.

In step 904, the indication indicating the flow through the light source is adjusted according to the conduction detection signal. The reference signal of the current value is adjusted to adjust the average current flowing through the light source, thereby adjusting the brightness of the light source. In one embodiment, the conduction detection signal TD indicating the conduction state of the TRIAC dimmer 104 coupled between the power source and the power converter is received by the luminance and color temperature controller 112, and the indication flow is adjusted based on the conduction detection signal TD. A reference signal of the target current value through the light source. In particular, the turn-on detection signal TD indicates the on state of the TRIAC element 202 in the TRIAC dimmer 104 (eg, the conduction angle between 0-180 degrees). The brightness and color temperature controller 112 can provide a reference signal REF (as detailed in FIGS. 4 and 5 above) corresponding to the conduction angle of the TRIAC dimmer 104 according to the conduction detection signal TD, and according to the reference signal REF at the 埠PWM A drive signal DRV is generated to adjust the average current flowing through the LED source (eg, current ILED1 or current ILED2).

In step 906, a switch monitoring signal is received, the switch monitoring signal (eg, the switch monitoring signal TS received by the brightness and color temperature controller 112) indicating an ON/OFF switch coupled between the power source and the power converter (eg, ON) /OFF switch 102) operation.

In step 908, the color temperature of the light source is adjusted based on the switch monitoring signal TS. For example, during a first time interval (eg, a time interval from time t2 to time t5 in FIG. 7), brightness and color temperature controller 112 may generate first control signal CTR1 to turn on the first having the first color temperature value. LED chain 120, and generating a second control signal CTR2 to turn off the second LED chain 130 having the second color temperature value such that the color temperature of the light source is adjusted to the first color temperature value; at a second time different from the first time interval During the interval (eg, the time interval from time t7 to time t8 in FIG. 7), the brightness and color temperature controller 112 may generate the first control signal CTR1 to turn off the first LED chain 120 and generate the second control signal CTR2. The second LED chain 130 is turned on so that the color temperature of the light source is adjusted to the second color temperature value.

In this way, the brightness and color temperature controller 112 can be opened not only according to ON/OFF. The operation of the backlight 102 adjusts the color temperature of the light source (eg, the first LED chain 120 and the second LED chain 130), and the LED light source can also be adjusted according to the operation of the TRIAC dimmer 104 (eg, the first LED chain 120 and the first The brightness of the two LED chains 130), without the need for additional dedicated components, is simple and convenient and saves costs.

The above description is exemplified based on an embodiment of an LED chain. However, embodiments in accordance with the invention may also be applied to other types of light sources. In other words, embodiments of the invention are not limited to LED light sources and are equally applicable to other types of light sources.

The wording and expressions used herein are for the purpose of illustration and description, and are not intended to be Various modifications are possible within the scope of the claims. Other modifications, variations, and alternatives may also be present. Accordingly, the claims are intended to cover all such equivalents.

Claims (20)

A light source driving circuit for adjusting brightness and color temperature of a light source, comprising: a power converter coupled between a power source and the light source, receiving an electric energy from the power source and providing an adjusted electric energy to the light source; a brightness and color temperature controller coupled to the power converter, receiving a conduction detection signal indicating a conduction angle of a three-terminal control dimmer coupled between the power source and the power converter, and based on the Turning on a detection signal to adjust the brightness of the light source, wherein the brightness and color temperature controller is further configured to receive a switch monitoring signal indicating an operation of an on/off switch coupled to the three-terminal control dimmer, and based on The switch monitors a signal to adjust the color temperature of the light source, wherein the brightness and color temperature controller comprises: a signal generator that generates a monitoring signal proportional to an average current flowing through the light source; and a three-terminal monitoring Receiving the conduction detection signal and generating a reference signal indicating a target value of the average current flowing through the light source according to the conduction detection signal; and a driving The signal generator and the three-terminal monitoring monitor are coupled to generate a driving signal according to the monitoring signal and the reference signal to control the adjusted power provided by the power converter to the light source. The light source driving circuit of claim 1, wherein the signal generator, the driver and a transformer of the power converter form a negative feedback loop, the negative feedback loop maintaining the average current flowing through the light source equal to the Target value. According to the light source driving circuit of claim 1, if the conduction detecting signal indicates that the conduction angle is increased, the three-terminal monitoring monitor increases the reference signal and the driver adjusts the driving signal to increase the flow rate. The average current of the light source; and if the conduction check The measurement signal indicates that the conduction angle is reduced, and the three-terminal monitoring monitor reduces the reference signal and the driver adjusts the driving signal to reduce the average current flowing through the light source. The light source driving circuit of claim 1, wherein the light source comprises: a first light emitting element having a first color temperature value and a second light emitting element having a second color temperature value, the brightness and color temperature controller The method includes: a color temperature control unit that generates a first control signal and a second control signal according to the switch monitoring signal, wherein the first control signal is selectively coupled to the brightness and color temperature controller and the first a first control switch between the light emitting elements to adjust the color temperature of the light source to the first color temperature value; the second control signal is selectively coupled to the brightness and color temperature controller and the second light emitting A second control switch between the components causes the color temperature of the light source to be adjusted to the second color temperature value. According to the light source driving circuit of claim 4, the color temperature control unit comprises: a timer, receiving the switch monitoring signal, starting timing when a falling edge of the switch monitoring signal occurs, and one at the falling edge a pulse signal is generated after a predefined time interval; a first D flip-flop receives the pulse signal; and a second D flip-flop is coupled to the first D flip-flop to receive the switch monitoring signal; The first control signal and the second control signal are generated based on an output signal of the second D flip-flop. The light source driving circuit of claim 1, wherein the brightness and color temperature controller comprises: a determining unit detects a power state of the brightness and color temperature controller, and generates a first determination signal and a second determination signal based on the brightness and color state of the color temperature controller, the brightness and color temperature controller is based on the The first determination signal, the second determination signal, and the switch monitoring signal adjust the color temperature of the light source. The light source driving circuit of claim 1, wherein the switch monitoring signal indicates that a time interval between an off operation and a next on operation of the on/off switch is less than a predetermined time interval, The brightness and color temperature controller adjusts the color temperature of the light source from a first color temperature value to a second color temperature value in response to the next turn-on operation of the on/off switch. The light source driving circuit of claim 1, wherein if the switch monitoring signal indicates that a time interval between an off operation of the on/off switch and a next on operation is greater than a predetermined time interval, The brightness and color temperature controller resets the color temperature of the light source to a preset color temperature value in response to the next turn-on operation of the on/off switch. The light source driving circuit of claim 1, further comprising: a rectifier, the power converter comprising: a transformer, the transformer comprising a primary winding, a secondary winding and an auxiliary winding, the primary winding is coupled The rectifier receives an electrical energy from the power source through the rectifier, the secondary winding provides the adjusted electrical energy to the light source, the auxiliary winding supplies power to the brightness and color temperature controller, the on/off switch and the three-terminal control A dimmer is coupled between the power source and the rectifier. The light source driving circuit of claim 1, wherein the brightness and color temperature controller is configured to receive a current monitoring signal indicative of a current flowing through the light source, and control the adjusted electrical energy based on the current monitoring signal. A brightness and color temperature controller for controlling brightness and color temperature of a light source, comprising: a signal generator for generating a monitoring signal proportional to an average current flowing through the light source; and a three-terminal monitoring monitor for receiving the indication coupling And a three-terminal controllable signal between a power source and a power converter for controlling a conduction angle of the dimmer and generating a target value indicating the average current flowing through the light source according to the conduction detection signal a reference signal; a driver coupled to the signal generator and the three-terminal monitoring monitor, generating a driving signal according to the monitoring signal and the reference signal to control the power converter to provide an adjusted power to the light source And a color temperature control unit receiving a switch monitoring signal indicating an operation of an on/off switch coupled to the three-terminal touch dimmer, and adjusting the color temperature of the light source based on the switch monitoring signal. A brightness and color temperature controller according to claim 11 wherein the signal generator, the driver and the transformer in the power converter form a negative feedback loop that maintains the average current flowing through the source equal to The target value. According to the brightness and color temperature controller of claim 11 , if the conduction detection signal indicates that the conduction angle is increased, the three-terminal monitoring monitor increases the reference signal and the driver adjusts the driving signal to increase the flow. The average current through the light source; and if the conduction detection signal indicates that the conduction angle is decreasing, the three-terminal monitoring monitor reduces the reference signal and the driver adjusts the driving signal to reduce the flow through the light source Average current. The brightness and color temperature controller according to claim 11 , wherein the light source comprises: a first light emitting element having a first color temperature value and a second light emitting element having a second color temperature value, the color temperature control unit Generating a first control signal and a second control according to the switch monitoring signal Signaling, the first control signal selectively turning on a first control switch coupled between the brightness and color temperature controller and the first light emitting element to adjust the color temperature of the light source to the first color temperature a second control signal selectively turning on a second control switch coupled between the brightness and color temperature controller and the second light emitting element to adjust the color temperature of the light source to the second color temperature value . The brightness and color temperature controller according to claim 14 , wherein the color temperature control unit comprises: a timer that receives the switch monitoring signal and starts timing when a falling edge of the switch monitoring signal occurs, at the falling edge a pulse signal is generated after a predefined time interval; a first D flip-flop receives the pulse signal; and a second D flip-flop is coupled to the first D flip-flop to receive the switch monitoring signal; The first control signal and the second control signal are generated based on an output signal of the second D flip-flop. The brightness and color temperature controller according to claim 11 , wherein the brightness and color temperature controller further comprises: a determining unit that detects a brightness state and a color temperature controller and based on the brightness and color temperature controller The power state generates a first determination signal and a second determination signal, and the brightness and color temperature controller adjusts the color temperature of the light source based on the first determination signal, the second determination signal, and the switch monitoring signal. According to the brightness and color temperature controller of claim 11, wherein if the switch monitoring signal indicates that a time interval between an open operation and a next open operation of the on/off switch is less than a predetermined time interval, The brightness and color temperature controller is responsive to the on/off switch The next turn-on operation adjusts the color temperature of the light source from a first color temperature value to a second color temperature value. The brightness and color temperature controller according to claim 17, wherein the light source comprises: a first light emitting element having the first color temperature value and a second light emitting element having the second color temperature value, wherein the brightness And the color temperature controller generates a first control signal and a second control signal to adjust the color temperature of the light source, when the first control signal is coupled to be coupled between the brightness and color temperature controller and the first light emitting element a first control switch, a current flows through the first light emitting element and a color temperature of the light source is adjusted to the first color temperature value; when the second control signal is coupled to the brightness and color temperature controller and the second When a second control switch is between the light-emitting elements, a current flows through the second light-emitting element and the color temperature of the light source is adjusted to the second color temperature value. The brightness and color temperature controller according to claim 11, wherein if the switch monitoring signal indicates that a time interval between an open operation and a next open operation of the on/off switch is greater than a predetermined time interval, The brightness and color temperature controller then resets the color temperature of the light source to a preset color temperature value in response to the next turn-on operation of the on/off switch. The brightness and color temperature controller according to claim 11 , wherein the three-terminal monitoring device comprises: a comparator for generating a square wave signal according to the conduction detection signal and a threshold voltage; and a filter according to the The square wave signal produces the reference signal.